Indian writer Kautilya (3rd century BCE) described gray diamonds as “having a gray color like the sheen of a polished blade, which brought all manner of good luck to the wearer.” This particular gray diamond in a ring by @Hemmerle weighs 10.67 carats and was graded Fancy gray, SI1 clarity by GIA. It was also classified as type IIb, which means it contains boron. This diamond was likely colored by boron and unidentified, plastic deformation-related defects that changed the hue from blue towards gray. For gray diamonds (with no modifying colors) boron is the rarest cause of color (roughly 10%). Fancy gray diamonds of this size and clarity are rare, and very few gray diamonds have appeared at auction in the past few years. Courtesy: @SothebysJewels